It is quite impossible to write down anything definite with regard to the length of time for which the lens must be uncovered. If we had only one particular subject to photograph, and this subject were always lighted by the same amount of daylight, it would be an easy matter to calculate the amount of exposure required with every diaphragm of a lens, provided that the necessary amount had been ascertained by experiment with but one of those diaphragms. For these stops or diaphragms, as furnished with modern lenses, have apertures bearing a definite relation to one another. As a general rule each diaphragm will require double the exposure needed for the next size larger. Or to put it in another way - suppose the smallest stop of a lens to require an exposure of 24. Seconds with a given subject, with the next size larger the exposure will be 12, then 6, then 3, then until we come to the full aperture of the lens, by which the picture can be taken in ofa second. But as a matter of fact, the exposure varies not only with the nature of the subject, but with the time of day, the time of year, and the state of the atmosphere. The old adage, Experientia can not be more aptly quoted than in connection with this question of exposure.
About the Publisher
Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com
This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.
Publisher - Forgotten Books
Language - English
Author(s) - A. Fellow of the Chemical Society
Published Date - August 26 2019
ISBN - 9780331669350
Dimesions - 22.9 x 15.2 x 1.3 cm
Page Count - 188
Payment & Security
Your payment information is processed securely. We do not store credit card details nor have access to your credit card information.